refactor: Complete Phase 3 - Migrate API route handlers from core to utilities

- Created dedicated utility functions for API route proxies (buildApiUrl, extractHeaders, handleApiError)
- Migrated all 20 API route handlers to use new utilities instead of api/core
- Routes continue to act as proxies to Rails API (correct architecture)
- Removed dependency on buildUrl from api/core in all route handlers
- Updated migration plan to reflect completed Phase 3

src/routes/api/_utils.ts

@@ -0,0 +1,55 @@
+import { PUBLIC_SIERO_API_URL } from '$env/static/public'
+
+/**
+ * Utility functions for API route handlers
+ * These routes act as proxies to the Rails API
+ */
+
+export const API_BASE = new URL(PUBLIC_SIERO_API_URL || 'http://localhost:3000').href
+
+/**
+ * Build a full URL for the Rails API
+ */
+export function buildApiUrl(path: string, params?: Record<string, any>): string {
+  const url = new URL(path.startsWith('http') ? path : `${API_BASE}${path}`, API_BASE)
+
+  if (params) {
+    for (const [key, value] of Object.entries(params)) {
+      if (value === undefined || value === null) continue
+      if (Array.isArray(value)) {
+        value.forEach((x) => url.searchParams.append(key, String(x)))
+      } else {
+        url.searchParams.set(key, String(value))
+      }
+    }
+  }
+
+  return url.toString()
+}
+
+/**
+ * Extract headers that should be forwarded to the Rails API
+ */
+export function extractHeaders(request: Request): Record<string, string> {
+  const headers: Record<string, string> = {
+    'Content-Type': 'application/json'
+  }
+
+  const editKey = request.headers.get('X-Edit-Key')
+  if (editKey) {
+    headers['X-Edit-Key'] = editKey
+  }
+
+  return headers
+}
+
+/**
+ * Common error handler for API routes
+ */
+export function handleApiError(error: any, action: string) {
+  console.error(`Error ${action}:`, error)
+  return {
+    error: `Failed to ${action}`,
+    details: error instanceof Error ? error.message : 'Unknown error'
+  }
+}

src/routes/api/parties/+server.ts

@@ -1,8 +1,5 @@
 import { json, type RequestHandler } from '@sveltejs/kit'
-import { buildUrl } from '$lib/api/core'
+import { buildApiUrl, extractHeaders, handleApiError } from '../_utils'
-import { PUBLIC_SIERO_API_URL } from '$env/static/public'
-
-const API_BASE = new URL(PUBLIC_SIERO_API_URL || 'http://localhost:3000').href
 
 /**
  * POST /api/parties - Create a new party
@@ -11,33 +8,19 @@ const API_BASE = new URL(PUBLIC_SIERO_API_URL || 'http://localhost:3000').href
 export const POST: RequestHandler = async ({ request, fetch }) => {
   try {
     const body = await request.json()
-    const editKey = request.headers.get('X-Edit-Key')
+    const headers = extractHeaders(request)
 
     // Forward to Rails API
     // The server-side fetch will automatically add Bearer token if user is authenticated
-    const response = await fetch(buildUrl('/parties'), {
+    const response = await fetch(buildApiUrl('/parties'), {
       method: 'POST',
-      headers: {
+      headers,
-        'Content-Type': 'application/json',
-        ...(editKey ? { 'X-Edit-Key': editKey } : {})
-      },
       body: JSON.stringify(body)
     })
 
     const data = await response.json()
-
-    // If creation was successful and returned an edit key, include it in response
-    if (response.ok) {
-      return json(data, { status: response.status })
-    }
-
-    // Forward error response
     return json(data, { status: response.status })
   } catch (error) {
-    console.error('Error creating party:', error)
+    return json(handleApiError(error, 'create party'), { status: 500 })
-    return json(
-      { error: 'Failed to create party' },
-      { status: 500 }
-    )
   }
 }

src/routes/api/parties/[id]/+server.ts

@@ -1,5 +1,5 @@
 import { json, type RequestHandler } from '@sveltejs/kit'
-import { buildUrl } from '$lib/api/core'
+import { buildApiUrl, extractHeaders, handleApiError } from '../../_utils'
 
 /**
  * PUT /api/parties/[id] - Update a party
@@ -11,41 +11,31 @@ export const PUT: RequestHandler = async ({ request, params, fetch }) => {
   try {
     const { id } = params
     const body = await request.json()
-    const editKey = request.headers.get('X-Edit-Key')
+    const headers = extractHeaders(request)
 
     // Forward to Rails API
-    const response = await fetch(buildUrl(`/parties/${id}`), {
+    const response = await fetch(buildApiUrl(`/parties/${id}`), {
       method: 'PUT',
-      headers: {
+      headers,
-        'Content-Type': 'application/json',
-        ...(editKey ? { 'X-Edit-Key': editKey } : {})
-      },
       body: JSON.stringify(body)
     })
 
     const data = await response.json()
     return json(data, { status: response.status })
   } catch (error) {
-    console.error('Error updating party:', error)
+    return json(handleApiError(error, 'update party'), { status: 500 })
-    return json(
-      { error: 'Failed to update party' },
-      { status: 500 }
-    )
   }
 }
 
 export const DELETE: RequestHandler = async ({ request, params, fetch }) => {
   try {
     const { id } = params
-    const editKey = request.headers.get('X-Edit-Key')
+    const headers = extractHeaders(request)
 
     // Forward to Rails API
-    const response = await fetch(buildUrl(`/parties/${id}`), {
+    const response = await fetch(buildApiUrl(`/parties/${id}`), {
       method: 'DELETE',
-      headers: {
+      headers
-        'Content-Type': 'application/json',
-        ...(editKey ? { 'X-Edit-Key': editKey } : {})
-      }
     })
 
     if (response.ok) {
@@ -57,10 +47,6 @@ export const DELETE: RequestHandler = async ({ request, params, fetch }) => {
     const errorData = await response.json().catch(() => ({}))
     return json(errorData, { status: response.status })
   } catch (error) {
-    console.error('Error deleting party:', error)
+    return json(handleApiError(error, 'delete party'), { status: 500 })
-    return json(
-      { error: 'Failed to delete party' },
-      { status: 500 }
-    )
   }
 }

src/routes/api/parties/[id]/characters/+server.ts

@@ -1,5 +1,5 @@
 import { json, type RequestHandler } from '@sveltejs/kit'
-import { buildUrl } from '$lib/api/core'
+import { buildApiUrl, extractHeaders, handleApiError } from '../../../_utils'
 
 /**
  * POST /api/parties/[id]/characters - Add character to party
@@ -25,7 +25,7 @@ export const POST: RequestHandler = async ({ request, params, fetch }) => {
     }
 
     // Forward to Rails API
-    const response = await fetch(buildUrl('/characters'), {
+    const response = await fetch(buildApiUrl('/characters'), {
       method: 'POST',
       headers: {
         'Content-Type': 'application/json',
@@ -51,7 +51,7 @@ export const DELETE: RequestHandler = async ({ request, params, fetch }) => {
     const editKey = request.headers.get('X-Edit-Key')
 
     // Forward to Rails API - use grid_characters endpoint with the ID
-    const response = await fetch(buildUrl(`/grid_characters/${body.gridCharacterId}`), {
+    const response = await fetch(buildApiUrl(`/grid_characters/${body.gridCharacterId}`), {
       method: 'DELETE',
       headers: {
         'Content-Type': 'application/json',

src/routes/api/parties/[id]/characters/[characterId]/+server.ts

@@ -1,5 +1,5 @@
 import { json, type RequestHandler } from '@sveltejs/kit'
-import { buildUrl } from '$lib/api/core'
+import { buildApiUrl, extractHeaders, handleApiError } from '../../../../_utils'
 
 /**
  * PUT /api/parties/[id]/characters/[characterId] - Update character in party
@@ -17,7 +17,7 @@ export const PUT: RequestHandler = async ({ request, params, fetch }) => {
     }
 
     // Forward to Rails API
-    const response = await fetch(buildUrl(`/grid_characters/${params.characterId}`), {
+    const response = await fetch(buildApiUrl(`/grid_characters/${params.characterId}`), {
       method: 'PUT',
       headers: {
         'Content-Type': 'application/json',

src/routes/api/parties/[id]/grid_characters/+server.ts

@@ -1,5 +1,5 @@
 import { json, type RequestHandler } from '@sveltejs/kit'
-import { buildUrl } from '$lib/api/core'
+import { buildApiUrl, extractHeaders, handleApiError } from '../../../_utils'
 
 /**
  * POST /api/parties/[id]/grid_characters - Add character to party
@@ -12,7 +12,7 @@ export const POST: RequestHandler = async ({ request, params, fetch, cookies })
 		const editKey = request.headers.get('X-Edit-Key')
 
 		// Forward to Rails API
-		const response = await fetch(buildUrl('/characters'), {
+		const response = await fetch(buildApiUrl('/characters'), {
 			method: 'POST',
 			headers: {
 				'Content-Type': 'application/json',

src/routes/api/parties/[id]/grid_characters/[characterId]/position/+server.ts

@@ -1,6 +1,6 @@
 import { json } from '@sveltejs/kit'
 import type { RequestHandler } from './$types'
-import { buildUrl } from '$lib/api/core'
+import { buildApiUrl, extractHeaders, handleApiError } from '../../../../../_utils'
 
 export const PUT: RequestHandler = async ({ params, request, fetch, cookies }) => {
 	const { id: partyId, characterId } = params
@@ -9,7 +9,7 @@ export const PUT: RequestHandler = async ({ params, request, fetch, cookies }) =
 
 	// Forward the request to the Rails API
 	const apiResponse = await fetch(
-		buildUrl(`/parties/${partyId}/grid_characters/${characterId}/position`),
+		buildApiUrl(`/parties/${partyId}/grid_characters/${characterId}/position`),
 		{
 			method: 'PUT',
 			headers: {

src/routes/api/parties/[id]/grid_characters/swap/+server.ts

@@ -1,6 +1,6 @@
 import { json } from '@sveltejs/kit'
 import type { RequestHandler } from './$types'
-import { buildUrl } from '$lib/api/core'
+import { buildApiUrl, extractHeaders, handleApiError } from '../../../../_utils'
 
 export const POST: RequestHandler = async ({ params, request, fetch, cookies }) => {
 	const { id: partyId } = params
@@ -9,7 +9,7 @@ export const POST: RequestHandler = async ({ params, request, fetch, cookies })
 
 	// Forward the request to the Rails API
 	const apiResponse = await fetch(
-		buildUrl(`/parties/${partyId}/grid_characters/swap`),
+		buildApiUrl(`/parties/${partyId}/grid_characters/swap`),
 		{
 			method: 'POST',
 			headers: {

src/routes/api/parties/[id]/grid_summons/+server.ts

@@ -1,5 +1,5 @@
 import { json, type RequestHandler } from '@sveltejs/kit'
-import { buildUrl } from '$lib/api/core'
+import { buildApiUrl, extractHeaders, handleApiError } from '../../../_utils'
 
 /**
  * POST /api/parties/[id]/grid_summons - Add summon to party
@@ -12,7 +12,7 @@ export const POST: RequestHandler = async ({ request, params, fetch, cookies })
 		const editKey = request.headers.get('X-Edit-Key')
 
 		// Forward to Rails API
-		const response = await fetch(buildUrl('/summons'), {
+		const response = await fetch(buildApiUrl('/summons'), {
 			method: 'POST',
 			headers: {
 				'Content-Type': 'application/json',

src/routes/api/parties/[id]/grid_summons/[summonId]/position/+server.ts

@@ -1,6 +1,6 @@
 import { json } from '@sveltejs/kit'
 import type { RequestHandler } from './$types'
-import { buildUrl } from '$lib/api/core'
+import { buildApiUrl, extractHeaders, handleApiError } from '../../../../../_utils'
 
 export const PUT: RequestHandler = async ({ params, request, fetch, cookies }) => {
 	const { id: partyId, summonId } = params
@@ -9,7 +9,7 @@ export const PUT: RequestHandler = async ({ params, request, fetch, cookies }) =
 
 	// Forward the request to the Rails API
 	const apiResponse = await fetch(
-		buildUrl(`/parties/${partyId}/grid_summons/${summonId}/position`),
+		buildApiUrl(`/parties/${partyId}/grid_summons/${summonId}/position`),
 		{
 			method: 'PUT',
 			headers: {

src/routes/api/parties/[id]/grid_summons/swap/+server.ts

@@ -1,6 +1,6 @@
 import { json } from '@sveltejs/kit'
 import type { RequestHandler } from './$types'
-import { buildUrl } from '$lib/api/core'
+import { buildApiUrl, extractHeaders, handleApiError } from '../../../../_utils'
 
 export const POST: RequestHandler = async ({ params, request, fetch, cookies }) => {
 	const { id: partyId } = params
@@ -9,7 +9,7 @@ export const POST: RequestHandler = async ({ params, request, fetch, cookies })
 
 	// Forward the request to the Rails API
 	const apiResponse = await fetch(
-		buildUrl(`/parties/${partyId}/grid_summons/swap`),
+		buildApiUrl(`/parties/${partyId}/grid_summons/swap`),
 		{
 			method: 'POST',
 			headers: {

src/routes/api/parties/[id]/grid_weapons/+server.ts

@@ -1,5 +1,5 @@
 import { json, type RequestHandler } from '@sveltejs/kit'
-import { buildUrl } from '$lib/api/core'
+import { buildApiUrl, extractHeaders, handleApiError } from '../../../_utils'
 
 /**
  * POST /api/parties/[id]/grid_weapons - Add weapon to party
@@ -9,16 +9,15 @@ import { buildUrl } from '$lib/api/core'
 export const POST: RequestHandler = async ({ request, params, fetch, cookies }) => {
 	try {
 		const body = await request.json()
-		const editKey = request.headers.get('X-Edit-Key')
+		const headers = {
+			...extractHeaders(request),
+			Authorization: `Bearer ${cookies.get('access_token')}`
+		}
 
 		// Forward to Rails API
-		const response = await fetch(buildUrl('/weapons'), {
+		const response = await fetch(buildApiUrl('/weapons'), {
 			method: 'POST',
-			headers: {
+			headers,
-				'Content-Type': 'application/json',
-				Authorization: `Bearer ${cookies.get('access_token')}`,
-				...(editKey ? { 'X-Edit-Key': editKey } : {})
-			},
 			body: JSON.stringify({
 				weapon: {
 					party_id: params.id,
@@ -30,10 +29,6 @@ export const POST: RequestHandler = async ({ request, params, fetch, cookies })
 		const data = await response.json()
 		return json(data, { status: response.status })
 	} catch (error) {
-		console.error('Error adding weapon:', error)
+		return json(handleApiError(error, 'add weapon'), { status: 500 })
-		return json(
-			{ error: 'Failed to add weapon' },
-			{ status: 500 }
-		)
 	}
 }

src/routes/api/parties/[id]/grid_weapons/[weaponId]/position/+server.ts

@@ -1,6 +1,6 @@
 import { json } from '@sveltejs/kit'
 import type { RequestHandler } from './$types'
-import { buildUrl } from '$lib/api/core'
+import { buildApiUrl, extractHeaders, handleApiError } from '../../../../../_utils'
 
 export const PUT: RequestHandler = async ({ params, request, fetch, cookies }) => {
 	const { id: partyId, weaponId } = params
@@ -9,7 +9,7 @@ export const PUT: RequestHandler = async ({ params, request, fetch, cookies }) =
 
 	// Forward the request to the Rails API
 	const apiResponse = await fetch(
-		buildUrl(`/parties/${partyId}/grid_weapons/${weaponId}/position`),
+		buildApiUrl(`/parties/${partyId}/grid_weapons/${weaponId}/position`),
 		{
 			method: 'PUT',
 			headers: {

src/routes/api/parties/[id]/grid_weapons/swap/+server.ts

@@ -1,6 +1,6 @@
 import { json } from '@sveltejs/kit'
 import type { RequestHandler } from './$types'
-import { buildUrl } from '$lib/api/core'
+import { buildApiUrl, extractHeaders, handleApiError } from '../../../../_utils'
 
 export const POST: RequestHandler = async ({ params, request, fetch, cookies }) => {
 	const { id: partyId } = params
@@ -9,7 +9,7 @@ export const POST: RequestHandler = async ({ params, request, fetch, cookies })
 
 	// Forward the request to the Rails API
 	const apiResponse = await fetch(
-		buildUrl(`/parties/${partyId}/grid_weapons/swap`),
+		buildApiUrl(`/parties/${partyId}/grid_weapons/swap`),
 		{
 			method: 'POST',
 			headers: {

src/routes/api/parties/[id]/summons/+server.ts

@@ -1,5 +1,5 @@
 import { json, type RequestHandler } from '@sveltejs/kit'
-import { buildUrl } from '$lib/api/core'
+import { buildApiUrl, extractHeaders, handleApiError } from '../../../_utils'
 
 /**
  * POST /api/parties/[id]/summons - Add summon to party
@@ -27,7 +27,7 @@ export const POST: RequestHandler = async ({ request, params, fetch }) => {
     }
 
     // Forward to Rails API
-    const response = await fetch(buildUrl('/summons'), {
+    const response = await fetch(buildApiUrl('/summons'), {
       method: 'POST',
       headers: {
         'Content-Type': 'application/json',
@@ -53,7 +53,7 @@ export const DELETE: RequestHandler = async ({ request, params, fetch }) => {
     const editKey = request.headers.get('X-Edit-Key')
 
     // Forward to Rails API - use grid_summons endpoint with the ID
-    const response = await fetch(buildUrl(`/grid_summons/${body.gridSummonId}`), {
+    const response = await fetch(buildApiUrl(`/grid_summons/${body.gridSummonId}`), {
       method: 'DELETE',
       headers: {
         'Content-Type': 'application/json',

src/routes/api/parties/[id]/summons/[summonId]/+server.ts

@@ -1,5 +1,5 @@
 import { json, type RequestHandler } from '@sveltejs/kit'
-import { buildUrl } from '$lib/api/core'
+import { buildApiUrl, extractHeaders, handleApiError } from '../../../../_utils'
 
 /**
  * PUT /api/parties/[id]/summons/[summonId] - Update summon in party
@@ -17,7 +17,7 @@ export const PUT: RequestHandler = async ({ request, params, fetch }) => {
     }
 
     // Forward to Rails API
-    const response = await fetch(buildUrl(`/grid_summons/${params.summonId}`), {
+    const response = await fetch(buildApiUrl(`/grid_summons/${params.summonId}`), {
       method: 'PUT',
       headers: {
         'Content-Type': 'application/json',

src/routes/api/parties/[id]/weapons/+server.ts

@@ -1,5 +1,5 @@
 import { json, type RequestHandler } from '@sveltejs/kit'
-import { buildUrl } from '$lib/api/core'
+import { buildApiUrl, extractHeaders, handleApiError } from '../../../_utils'
 
 /**
  * POST /api/parties/[id]/weapons - Add weapon to party
@@ -26,7 +26,7 @@ export const POST: RequestHandler = async ({ request, params, fetch }) => {
     }
 
     // Forward to Rails API
-    const response = await fetch(buildUrl('/weapons'), {
+    const response = await fetch(buildApiUrl('/weapons'), {
       method: 'POST',
       headers: {
         'Content-Type': 'application/json',
@@ -38,7 +38,7 @@ export const POST: RequestHandler = async ({ request, params, fetch }) => {
     const data = await response.json()
     return json(data, { status: response.status })
   } catch (error) {
-    console.error('Error adding weapon:', error)
+    return json(handleApiError(error, 'adding weapon'), { status: 500 })
     return json(
       { error: 'Failed to add weapon' },
       { status: 500 }
@@ -54,7 +54,7 @@ export const DELETE: RequestHandler = async ({ request, params, fetch }) => {
     console.log('DELETE weapon request:', { body, params })
 
     // Forward to Rails API - use grid_weapons endpoint with the ID
-    const response = await fetch(buildUrl(`/grid_weapons/${body.gridWeaponId}`), {
+    const response = await fetch(buildApiUrl(`/grid_weapons/${body.gridWeaponId}`), {
       method: 'DELETE',
       headers: {
         'Content-Type': 'application/json',
@@ -72,7 +72,7 @@ export const DELETE: RequestHandler = async ({ request, params, fetch }) => {
     const errorData = await response.json().catch(() => ({}))
     return json(errorData, { status: response.status })
   } catch (error) {
-    console.error('Error removing weapon:', error)
+    return json(handleApiError(error, 'removing weapon'), { status: 500 })
     return json(
       { error: 'Failed to remove weapon' },
       { status: 500 }

src/routes/api/parties/[id]/weapons/[weaponId]/+server.ts

@@ -1,5 +1,5 @@
 import { json, type RequestHandler } from '@sveltejs/kit'
-import { buildUrl } from '$lib/api/core'
+import { buildApiUrl, extractHeaders, handleApiError } from '../../../../_utils'
 
 /**
  * PUT /api/parties/[id]/weapons/[weaponId] - Update weapon in party
@@ -17,7 +17,7 @@ export const PUT: RequestHandler = async ({ request, params, fetch }) => {
     }
 
     // Forward to Rails API
-    const response = await fetch(buildUrl(`/grid_weapons/${params.weaponId}`), {
+    const response = await fetch(buildApiUrl(`/grid_weapons/${params.weaponId}`), {
       method: 'PUT',
       headers: {
         'Content-Type': 'application/json',
@@ -29,7 +29,7 @@ export const PUT: RequestHandler = async ({ request, params, fetch }) => {
     const data = await response.json()
     return json(data, { status: response.status })
   } catch (error) {
-    console.error('Error updating weapon:', error)
+    return json(handleApiError(error, 'updating weapon'), { status: 500 })
     return json(
       { error: 'Failed to update weapon' },
       { status: 500 }

src/routes/api/uncap/characters/+server.ts

@@ -1,5 +1,5 @@
 import { json, type RequestHandler } from '@sveltejs/kit'
-import { buildUrl } from '$lib/api/core'
+import { buildApiUrl, extractHeaders, handleApiError } from '../../_utils'
 
 export const POST: RequestHandler = async ({ request, fetch }) => {
 	try {
@@ -7,7 +7,7 @@ export const POST: RequestHandler = async ({ request, fetch }) => {
 		const editKey = request.headers.get('X-Edit-Key')
 
 		// Forward to Rails API with automatic auth via handleFetch
-		const response = await fetch(buildUrl('/characters/update_uncap'), {
+		const response = await fetch(buildApiUrl('/characters/update_uncap'), {
 			method: 'POST',
 			headers: {
 				'Content-Type': 'application/json',

src/routes/api/uncap/summons/+server.ts

@@ -1,5 +1,5 @@
 import { json, type RequestHandler } from '@sveltejs/kit'
-import { buildUrl } from '$lib/api/core'
+import { buildApiUrl, extractHeaders, handleApiError } from '../../_utils'
 
 export const POST: RequestHandler = async ({ request, fetch }) => {
 	try {
@@ -7,7 +7,7 @@ export const POST: RequestHandler = async ({ request, fetch }) => {
 		const editKey = request.headers.get('X-Edit-Key')
 
 		// Forward to Rails API with automatic auth via handleFetch
-		const response = await fetch(buildUrl('/summons/update_uncap'), {
+		const response = await fetch(buildApiUrl('/summons/update_uncap'), {
 			method: 'POST',
 			headers: {
 				'Content-Type': 'application/json',

src/routes/api/uncap/weapons/+server.ts

@@ -1,5 +1,5 @@
 import { json, type RequestHandler } from '@sveltejs/kit'
-import { buildUrl } from '$lib/api/core'
+import { buildApiUrl, extractHeaders, handleApiError } from '../../_utils'
 
 export const POST: RequestHandler = async ({ request, fetch }) => {
 	try {
@@ -7,7 +7,7 @@ export const POST: RequestHandler = async ({ request, fetch }) => {
 		const editKey = request.headers.get('X-Edit-Key')
 
 		// Forward to Rails API with automatic auth via handleFetch
-		const response = await fetch(buildUrl('/weapons/update_uncap'), {
+		const response = await fetch(buildApiUrl('/weapons/update_uncap'), {
 			method: 'POST',
 			headers: {
 				'Content-Type': 'application/json',